IMPROVED FATIGUE RESISTANCE OF SINTERED STEELS VIA LOCAL HARDENING

The aim at the present paper was to find out how the local hardening via surface modification and also microstructures affect the fatigue characteristics of the considered sintered materials. Two different systems were prepared: as-sintered and shot peened prealloyed sintered (Astaloy CrL based) steels with addition of 0.5 and 0.7 % C. Fatigue tests were carried out in symmetric plane bending at R= -1. The detailed research of local area showed local hardening caused by surface modification via shot peening. Local hardening exhibit positive effect on the fatigue failure resistance, due to a surface something close to a fully densified surface layer obtained by shot peening, as well as by the elimination of the detrimental effect of pores near the surface.